Electric meter.



0. E. J-. OKEENAN. ELEGTRIG METER. APPLICATION FILED JUNE 28, 1909.

Patented ay 10, mm.

ANDREW a GRAHAM c0. PMOTO-UIHOGRAPNERS. WASHINGTON n. c.

0. E. J. OKEENAN.

BLEGTBIG METER. APPLIUATION FILED JUNE 28, 1909.

Patented May 10, 1910.

aNDREw a QRMAM 00. PHOTDALWNOGRAPHERS. WASHINGTON, n c

CHARLES IEDOUARD JULES OKEENAIN', OF ST. CLOUD, FRANCE.

ELECTRIC METER.

QTY/I92.

Specification of Letters Patent.

Patented May 1W, iwlfl.

Application filed June 28, 1909. Serial No. 504,845.

" all whom it may concern:

Be it known that I, CHARLES EDOUARD JULns OKEENAN, a citizen of the French Republic, residing at 5 Rue des Grands Champs, St. Cloud, in France, have invented certain new and useful Improvements in Electric Meters, of which the following is a specification.

The present invention enables one, by means of a new. device to obtain a fall of potential (or an electric current) proportional to the watts absorbed in a continuous current circuit. This fall of potential or this current can then act on the armature of a meter (such as that patented by me in the United States on January 9, 1900, No. 641,140 known under the name of the OK. meter) or upon the armature of any other suitable meter whether provided with a brake or not, thus forming a watt-hour meter; or this fall of potential (or current) could act on a millivoltmeter ammeter of the Weston, Ohauvin and Arnoux, Deprez-dArsonval, ll/Ieylan dArsonval or other type, so as to form a wattmeter which can be read directly.

In the accompanying drawings Figure 1 represents diagrammatically one form of my improved meter. Fig. 2 is a similar diagrammatic View of a slightly modified form. Fig. 3 is a side view showing the construction of the shunt portion of the me- .ter. Fig. 4: is a similar view showing part of the shunt incased in vacuum tubes. Fig. 5 is a diagrammatic view showing the complete meter. Figs. 6 and 7 are diagrammatic views showing diiferent arrangements of shunt and motor, and Figs. 8 and 9 are diagrammatic views showing modifications.

Suppose A B to be the shunt of an OK. meter (Fig. 1) traversed by a continuous current in the direction of the double arrows, it is known that under these conditions there will be a fall in potential between points A and B proportional to the intensity of the current passing through it and that since the ends of the circuits of the armature of the motor are divided at A and B, the said motor will revolve at a speed proportional to the number of volts-hours pro duced at the terminals of the shunt and consequently proportional to the number of ampores-hours absorbed by the consumer.

In the new arrangement between the points A and B of the shunt is connected a copper or nickel wire A. C B; this wire derives a more or less important part of the current primarily passing through the shunt, 111 accordance with the well known law of derived currents.

Around the portion of the wire desig nated C B to which the applicant gives the name of sub-shunt is coiled a long winding Z) of fine German silver wire or of some conductor having a negative temperature coeflicient. The ends of this winding are connected to the points A and A between which there exists a difference of potential U which, multiplied by the current I, represents the number of watts absorbed by the consumer; this fine wire-coil is warmed by the current due to the potential difference U and also warms the sub-shunt G B which it incloses. Now the warming of the coil and consequently of the wire G B is proportional to the square of the current passing through the coil, that is to say to the square of the dilference of potential U. But according to a development of the well known binomial theorem, it is known that between certain limits, a sufiiciently approximate proportionality exists between the increase in a function which is proportional to the square U of a variable, and the increase in this variable U, provided that this increase is sufficiently small. The result is that the variation in degrees centigrade in the temperature of the coil and of the wire C B is proportional to the variations in U, within certain limits, provided of course that sufficient time is allowed for the temperature equilibrium to establish itself on each occasion. Now when the temperature 6) of the wire or subshunt rises, its coefiicient of temperature it causes the resistance therein to increase, so that the current passing through the subshunt diminishes, but as the resistance of the wire A 0 remains on the contrary practically constant, the result is that finally, the fall in potential at the terminals of the subshunt C B is increased, for the current diminishes less, in proportion, in the subshunt than the resistance of the said subshunt increases and the product, 2' 1" :u, of the potential at its terminals, Fig. 6, is increased when U is increased.

From the foregoing it follows that a point D can be found in the shunt A B which point in certain cases can coincide with the point B of the subshunt as in Fig. 7, such that the difference of the potentials u" (or current) between points C and D are proportional, when temperature equilibrium is established, to the watts absorbed at the same time in the installation, moreover this difference in potential (or current) is not sensibly affected by variations either of the surrounding temperature, or of the heating due to the current derived from the shunt A B which passes through the wires A C, C B and C D, provided that care is taken in the construction to arrange that the increases in temperature due to the heating produced by these currents, are practically identical. This can be provided for by covering these wires to a greater or less extent determined by experiment, with heat insulating substances such as cotton wool, glass wool or other suitable material, or by bringing their windings closer together or by any other suitable means. One could also, in order to avoid the effect of the heat: ing of the wire A C B by current derived from shunt A B, diminish this said current by making the ohmic resistance of this wire A C B sufliciently great.

In a case where the device M is a motor or an electrolytic meter, the same current can be used if desired to compound the said meter as is done at present in the OK. mo tor or in the Wright electrolytic meter, by means of introducing a very small constant fall of additional potential. That is obtained in Fig. 2 by means of the portion F G of the wire which is traversed by the fine wire current, the motor or the electrolyte M being connected between F and D in stead of between C and D.

Fig. 3 shows a practical form of the present invention.

f is a small coil of wire of copper or of nickel or other suitable metal covered with silk or other appropriate substance, and represents the wire A C in the diagram, f is another small coil of copper or nickel wire covered with silk or other material suitable for the purpose constituting the watt metric subshunt, Z) is a section through the coil of fine heating wire intended to be traversed by the current due to the potential U.

9 represents a kind of sheath of cottonwool or other suitable material, intended to diminish the loss of heat from the wire Z) so that the internal temperature of the coil Z) and of the sub-shunt f ean'be raised sufiiciently with a slight expenditure of power in the fine wire. It must be remarked how ever that this process of sheathingincreases the time of shifting between the variation of U and the variation of the temperature corresponding to a new equilibrium. This would not generally be an inconvenience for the meters but when the shifting of these two quantities is to be reduced, the thickness of the heat insulator g may be diminished and one could even suppress it completely in certain cases. Instead of using cotton-wool. or a heat insulator, one could diminish the loss by convection by placing the coils f and b, and if desired 7, in one or two vacuum tubes 0 and 0 (Figs. 4t and 5) and at will by using iron as the metal with a great positive coefiicient of temperature instead of copper or nickel, as is done in the additional resistances in the Nernst lamps, or some other suitable metal, such as steel. These metals could also if desired be exposed directly to the air, being protected from oxidation by suitable processes.

If instead of devices designed for acting with a variable current in a network having an almost constant potential as in the cases mentioned above, it is desired to use the same system to measure watts in the case of a current substantially constant with a variable potential, as in the Bernstein or Thury systems, where the translating devices are all included in the same circuit, one could use one of the arrangements shown diagrammatically in Figs. 8 and 9, which are very similar to those already shown for variable current and almost constant potential, and can be understood at a glance. The principal differences consist solely in that the heating coil 6 instead of being traversed by the potential current is traversed by the main current (or a derivation of this current is preferred) while the sub-shunt B C is traversed by the potential current or a derivation of this current. In this manner voltmeters may be transformed into watt meters and volt hour meters into watt hour meters.

Instead of transforming an ampere hour meter or volt hour meter into a watt hour meter one could transform a galvanoineter of the Deprez dArsonval type (with or without mirror) or a millivolt meter ammeter of the lVeston or other type into direct reading shunt Watt meters. Supposing M to be a lVeston millivoltmeter, connections with the sub-shunt may be made with the wires of the vacuum tube as shown for example in Fig. 5, and the apparatus will indicate directly on a proper scale the watts absorbed by the installation Z Z for example.

If preferred the apparatus could operate with the sub-shunt exposed to the air and surrounded or not, by cotton-wool or some other suitable heat insulating substance.

The same device can be used in the same way to transform Meylan dArsonval, Chauvin-Arnoux or other annneters into wattmeters as will be obvious without further explanation. In t 'ansforming these latter apparatus there is no necessity for compoundage such as described above, for the purpose of balancing the friction in the UK. or other meters or the counter electromotive forces of electrolysis in the case of \Vright or other electrolytic-meters.

In the case of a calorific shunt alnineter, the subshunt enables the Watts absorbed in alternating current circuits to be measured.

I claim 1. In a device for obtaining a fall of potential proportional to the Watts absorbed in a continuous current circuit, the combination of a shunt, a sub-shunt, and a Winding for heating the sub-shunt, the ends 01": said Winding being connected to the main conductors of the installation substantially as described.

2. In a device for obtaining a fall of potential proportional to the Watts absorbed in a continuous current circuit, the combination of a shunt, a sub-shunt, a Winding for heating the sub-shunt, the ends of said Winding being connected to the main conductors of the installation, and a motor meter connected between the sub-shunt and the shunt, substantially as described.

In Witness whereof I have hereunto set my hand this 16th day of June, 1909, in presence of two subscribing Witnesses.

CHARLES EDOUARD JULES OKEENAN.

Witnesses H. C. COKE, MAURICE H. PIGNET. 

